Touch panel input device and gesture detecting method

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese patent application no. 2010-232410 filed on Oct. 15, 2010, the contents of which are incorporated by reference for all purposes.

TECHNICAL FIELD

The present invention is related to a touch panel input device, and more specifically to a resistive film type touch panel input device.

In addition, the present invention is related to a gesture detecting method that employs the touch panel input device.

BACKGROUND

There are known resistive film type touch panel input devices having two dimensional touch input surfaces, that can detect the positions of points (touch points) on the touch input surfaces contacted by fingers or the like, as disclosed in Japanese Unexamined Patent Publication No. 2000-105645; Japanese Unexamined Patent Publication No. 2007-122522; and US Published Patent Application No. 2009/0322700.

This type of touch panel input device is basically constituted by: two resistive films which are arranged to face each other with a minute gap therebetween; an electrode pair (X electrode pair) formed by electrodes provided at the edges that face each other of one of the resistive films; an electrode pair (Y electrode pair) formed by electrodes provided at the edges of the other one of the resistive films that face each other and extend in directions perpendicular to the X electrode pair; means for applying voltages between the X electrode pair and between the Y electrode pair; and means for measuring the voltage which is divided at a touch point, when the resistive films are caused to contact each other by being touched.

In the configuration described above, the divided voltage which is measured between the X electrode pair corresponds to the resistance value of the resistive film from one of the electrodes to the touch point, that is, the distance between the electrode and the touch point. Therefore, the position of the touch point in the X direction can be detected by measuring this voltage. The same applies to the divided voltage which is measured between the Y electrode pair, and the position of the touch point in the Y direction is also detected. The two dimensional position of the touch point is detected in this manner.

Note that in touch panel input devices having the configuration described above, when two points are touched simultaneously, the voltage measured in the manner described above indicates an intermediate value between a value which is measured when one of the two points is touched and a value which is measured when the other of the two points is touched. Therefore, the substantial midpoint between the two points is detected. This point is disclosed in all of Japanese Unexamined Patent Publication No. 2000-105645; Japanese Unexamined Patent Publication No. 2007-122522; and US Published Patent Application No. 2009/0322700.

Meanwhile, US Published Patent Application No. 2009/0322700 in particular also discloses that it is possible to detect the distances between two touch points in touch panel input devices having the configuration described above, when two points are touched simultaneously. That is, when voltage is applied between one of the electrode pairs of the resistive films and two points are touched simultaneously, the resistance value between the electrodes is determined by the total resistance value of the resistive film, the two touch resistance values, and the resistance value between the two points within the other resistive film. Accordingly, the resistance value between the two points and the value of current that flows between the electrode pair will correspond to each other, and the resistance value between the two points is proportional to the distance between the two points. Therefore, the distance between the two points can be detected by measuring the current value that flows between the electrode pair.

US Published Patent Application No. 2009/0322700 also discloses that gestures, such as those in which the two touch points separate from each other, those in which the two touch points approach each other, and those in which the two tough points rotate with their approximate midpoint as the center of rotation, may be detected based on the above principle.

However, the touch panel input device disclosed in US Published Patent Application No. 2009/0322700 does not enable gestures more complex than those listed above to be detected. This point is common to conventional known resistive film type touch panel input devices.

SUMMARY

The present invention has been developed in view of the foregoing circumstances. It is an object of the present invention to provide a resistive film type touch panel input device which is capable of detecting complex gestures involving two touched points.

It is another object of the present invention to provide a method that enables detection of complex gestures input by two touched points, using such a touch panel input device.

A touch panel input device of the present invention comprises two resistive films which are arranged to face each other with a minute gap therebetween; a first electrode pair formed by electrodes provided at the edges of one of the resistive films that face each other; a second electrode pair formed by electrodes provided at the edges of the other one of the resistive films that face each other and extend in directions perpendicular to the first electrode pair; means for applying voltages between the first electrode pair and between the second electrode pair; means for measuring the voltage which is divided at two touch points with respect to the first electrode pair and the second electrode pair, when the resistive films are caused to contact each other by being touched at two points; means for measuring currents that flow between the first electrode pair and between the second electrode pairs when the touch occurs; and discriminating means, for discriminating the trajectories of the two touch points based on the values of the measured voltages and currents.

Note that the first and second electrode pairs are the same as the X electrode pair and the Y electrode pair of conventional devices described previously.

Note that it is desirable for the discriminating means to discriminate the trajectories based on the direction of change of the divided voltages and/or the currents. Further, the discriminating means may discriminate the trajectories based on the amount of change of the divided voltages and/or the currents per unit time.

In the touch panel input device of the present invention, it is desirable for the means for measuring the divided voltages and the means for measuring the currents to be configured to perform measurements during different periods of time.

A gesture detecting method of the present invention is for a touch panel input device equipped with two resistive films which are arranged to face each other with a minute gap therebetween, a first electrode pair formed by electrodes provided at the edges of one of the resistive films that face each other, and a second electrode pair formed by electrodes provided at the edges of the other one of the resistive films that face each other and extend in directions perpendicular to the first electrode pair. The method comprises applying voltages between the first electrode pair and the second electrode pair; measuring voltage which is divided at two touch points with respect to the first electrode pair and the second electrode pair and currents that flow between the first electrode pair and between the second electrode pairs, when the resistive films are caused to contact each other by being touched at two points; and discriminating the trajectories of the two touch points based on the values of the measured voltages and currents.

Note that in the gesture detecting method of the present invention, it is desirable for the trajectories to be discriminated based on the direction of change of the divided voltages and/or the currents. Further, the trajectories may be discriminated based on the amount of change of the divided voltages and/or the currents per unit time

In the gesture detecting method of the present invention, it is desirable for the divided voltages and the currents to be measured during different periods of time.

As described above, the touch panel input device of the present invention is equipped with the two resistive films, the first electrode pair, the second electrode pair, the voltage applying means, the voltage measuring means, the current measuring means, and the discriminating means. When the resistive films are touched at two touch points, the discriminating means obtains the position of the approximate midpoint between the two touch points, based on the voltage measured by the voltage measuring means, that is, the voltage divided between the first electrode pair and the second electrode pair by the touch points. In addition, the discriminating means obtains the distance between the two touch points based on the currents that flow between the first electrode pair and the second electrode pair. If the position of the approximate midpoint and the distance between two touch points can be determined, it is possible to detect how the two touch points are moving as a whole, and also how the distance between the two touch points is changing. Therefore, detection of complex gestures input by two touch points, which had heretofore been impossible using conventional devices, becomes possible.

In addition, the gestures detecting method is used in a touch panel input device equipped with the two resistive films, the first electrode pairs, and the second electrode pair, as described above. Voltages are applied between the first electrode pair and the second electrode pair, and the voltages divided by touch points between the first electrode pair and the second electrode pair, and the currents that flow between the first electrode pair and the second electrode pair are measured when one of the resistive films is caused to contact the other resistive films by being touched at two touch points. The trajectories of the two touch points are discriminated based on the values of the measured voltages and currents. Therefore, detection of complex gestures input by two touch points becomes possible.

Note that in the case that the divided voltages and the currents are respectively measured during different periods of time, more accurate measurement of these values will become possible.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idrefs="DRAWINGS">FIG. 1</figref> shows a perspective view that illustrates the schematic structure of a touch panel input apparatus according to an embodiment of the present invention.

<figref idrefs="DRAWINGS">FIG. 2</figref> shows a circuit diagram that illustrates the electrical structure of the touch panel input device.

<figref idrefs="DRAWINGS">FIG. 3</figref> shows a schematic side view that illustrates the state of two resistive films of the touch panel input device.

<figref idrefs="DRAWINGS">FIG. 4</figref> shows a schematic side view that illustrates a state in which the resistive films are touched at a single point.

<figref idrefs="DRAWINGS">FIG. 5</figref> shows a schematic side view that illustrates a state in which the resistive films are touched at two points.

<figref idrefs="DRAWINGS">FIG. 6</figref> shows an equivalence circuit diagram of the resistive films when no touch is being applied to the touch panel input device.

<figref idrefs="DRAWINGS">FIG. 7</figref> shows an equivalence circuit diagram of the resistive films when the touch panel input device is being touched at a single point.

<figref idrefs="DRAWINGS">FIG. 8</figref> shows an equivalence circuit diagram of the resistive films when the touch panel input device is being touched at two points.

<figref idrefs="DRAWINGS">FIG. 9</figref> shows schematic diagrams that illustrate examples of trajectories of touch points on the touch panel input device.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. <figref idrefs="DRAWINGS">FIG. 1</figref> illustrates the schematic structure of a touch panel input apparatus according to an embodiment of the present invention. The touch panel input device <b>1</b> includes: a rectangular resistive film <b>11</b> provided on a base plate <b>10</b>; a resistive film <b>12</b> provided as a cover sheet on the resistive film <b>11</b> with a minute space therebetween; electrodes <b>13</b> and <b>14</b> which are fixed to the left and right edges (in the drawing) of the resistive sheet <b>11</b> such that they are electrically connected to the resistive film <b>11</b>; and electrodes <b>15</b> and <b>16</b> which are fixed to the upper and lower edges (in the drawing) of the resistive sheet <b>12</b> such that they are electrically connected to the resistive film <b>12</b>. The electrodes <b>13</b> through <b>16</b> are connected to a control circuit <b>20</b>. A DC power source <b>21</b> and a discriminating section <b>22</b> are connected to the control circuit <b>20</b>.

The resistive films <b>11</b> and <b>12</b> are constituted by thin film like substrates formed by polyethylene terephthalate (PET), and layers of conductive films having uniform electrical resistivity formed thereof. The resistive films <b>11</b> and <b>12</b> are provided such that the surfaces on which the conductive films are formed face each other. By interposing insulative spacers (not shown), a minute gap is formed between the resistive films <b>11</b> and <b>12</b> in a normal state. Note that the resistive film <b>11</b> may be formed as a film coated directly on the base plate, without using the aforementioned substrate.

In the case that the base plate <b>10</b> has display elements, such as liquid crystal display elements, formed on the upper surface thereof, the contents displayed by the display elements and input by the touch panel input device <b>1</b> can be linked. In this case, it is desirable for the resistive films <b>11</b> and <b>12</b> to be formed by transparent materials. Examples of materials for such transparent resistive films <b>11</b> and <b>12</b> include: indium tin oxide (ITO); conductive polymers; and carbon nanotube containing organic films.

The electrodes <b>13</b> and <b>14</b> face each other in the X direction in <figref idrefs="DRAWINGS">FIG. 1</figref>, that is, a direction parallel to the upper and lower edges of the resistive films <b>11</b> and <b>12</b> in the drawing. The pair of electrodes <b>13</b> and <b>14</b> will be referred to as an X electrode pair (first electrode pair). The electrodes <b>15</b> and <b>16</b> face each other in the Y direction in <figref idrefs="DRAWINGS">FIG. 1</figref>, that is, a direction parallel to the left and right edges of the resistive films <b>11</b> and <b>12</b> in the drawing. The pair of electrodes <b>15</b> and <b>16</b> will be referred to as a Y electrode pair (second electrode pair).

Next, the control circuit <b>20</b> will be described in detail with reference to <figref idrefs="DRAWINGS">FIG. 2</figref>. As illustrated in <figref idrefs="DRAWINGS">FIG. 2</figref>, the control circuit <b>20</b> includes: a voltmeter <b>30</b> for measuring divided DC voltage to be described later; a converting circuit <b>31</b> for converting the output of the voltmeter <b>30</b> to voltage signals within a predetermined range; and an A/D converter <b>32</b>, for converting analog signals output by the converting circuit <b>31</b> into digital signals. In addition, the control circuit <b>20</b> includes: an ammeter <b>40</b> for measuring DC current to be described later; a converting circuit <b>41</b> for converting the output of the ammeter <b>40</b> to voltage signals within a predetermined range; and an A/D converter <b>42</b>, for converting analog signals output by the converting circuit <b>41</b> into digital signals.

Further, the control circuit <b>20</b> includes: a switch SW<b>1</b> provided along a path that connects the electrode <b>13</b> fixed to the resistive film <b>11</b> to the DC power source <b>21</b>; a switch SW<b>2</b> provided along a path that connects the electrode <b>15</b> fixed to the resistive film <b>12</b> to the DC power source <b>21</b>; a switch SW<b>3</b> that selectively connects either of the two paths or neither of the two paths (intermediate position) to the voltmeter <b>30</b>; a switch SW<b>4</b> provided along a path that connects the electrode <b>14</b> fixed to the resistive film <b>11</b> to the ammeter <b>40</b>; a switch SW<b>5</b> provided along a path that connects the electrode <b>15</b> fixed to the resistive film <b>12</b> to the ammeter <b>40</b>; and a switch SW<b>6</b> that selectively connects the switches SW<b>4</b> and SW<b>5</b> to the ammeter <b>40</b> or to ground.

The control circuit <b>20</b> configured as described above may be constituted by discrete circuits, or by integrated circuits. The discriminating section <b>22</b> illustrated in <figref idrefs="DRAWINGS">FIG. 1</figref> is generally constituted by a microcomputer or the like.

Next, the operation of the touch panel input device <b>1</b> will be described. A state in which the resistive film <b>12</b> toward the surface of the touch panel input device <b>1</b> is not being touched is illustrated in the schematic section view of <figref idrefs="DRAWINGS">FIG. 3</figref>. <figref idrefs="DRAWINGS">FIG. 4</figref> schematically illustrates a state in which the resistive film <b>12</b> is being touched at a single touch point <b>50</b>, and <figref idrefs="DRAWINGS">FIG. 5</figref> schematically illustrates a state in which the resistive film <b>12</b> is being touched at two touch points <b>51</b> and <b>52</b>.

The touch points are detected as will be described below. During detection of touch input, the control circuit <b>20</b> of <figref idrefs="DRAWINGS">FIG. 2</figref> sets the switches included therein as follows during periods (a) through (d) below.

(a) Switch SW<b>1</b>: Closed; Switch SW<b>2</b>: Open; Switch SW<b>3</b>: Connected with electrode <b>15</b>; Switch SW<b>4</b>: Closed; Switch SW<b>5</b>: Open; Switch SW<b>6</b>: Connected to ground; (b) Switches SW<b>1</b>, SW<b>2</b>, SW<b>4</b>, and SW<b>5</b>: The same state as during period (a), Switch SW<b>3</b>: Intermediate position (connected to neither the electrode <b>13</b> nor the electrode <b>15</b>); Switch SW<b>6</b>: Connected to ammeter <b>40</b>; (c) Switch SW<b>1</b>: Open; Switch SW<b>2</b>: Closed; Switch SW<b>3</b>: Connected with electrode <b>13</b>; Switch SW<b>4</b>: Open; Switch SW<b>5</b>: Closed; Switch SW<b>6</b>: Connected to ground (d) Switches SW<b>1</b>, SW<b>2</b>, SW<b>4</b>, and SW<b>5</b>: The same state as during period (c), Switch SW<b>3</b>: Intermediate position; Switch SW<b>6</b>: Connected to ammeter <b>40</b>. The lengths of periods (a) through (d) are predetermined and extremely short, and the periods (a) through (d) are cyclically repeated as (a), (b), (c), (d), (a), (b), . . . Note that <figref idrefs="DRAWINGS">FIG. 2</figref> illustrates a state during period (a) above.

During periods (a) and (b), the positions of the touch points and the interval between the touch points in the X direction are obtained, and during periods (c) and (d), the positions of the touch points and the interval between the touch points in the Y direction are obtained.

That is, in the case that the touch input is at a single touch point as illustrated in <figref idrefs="DRAWINGS">FIG. 4</figref> during period (a), the equivalence circuit of the resistive films <b>11</b> and <b>12</b>, etc. is that illustrated in <figref idrefs="DRAWINGS">FIG. 6</figref>. Note that in <figref idrefs="DRAWINGS">FIG. 6</figref>, Rx denotes the resistance of the resistive film <b>11</b>, Ry denotes the resistance of the resistive film <b>12</b>, and Rt denotes contact resistance (the same applies to the following Figures). The DC voltage which is being applied between the electrodes <b>13</b> and <b>14</b> of the resistive film <b>11</b> by the DC power source <b>21</b> is divided by the touch point <b>50</b>. The divided voltage is measured by the voltmeter via the contact resistance Rt and the resistance Ry of the resistive film <b>12</b>. The divided voltage corresponds to the resistance of the resistive film <b>11</b> from the electrode <b>13</b> to the touch point, that is, the distance therebetween. Therefore, the distance from the electrode <b>13</b> to the touch point, that is, the position of the touch point in the X direction, can be obtained based on the voltage measured by the voltmeter <b>30</b>.

Meanwhile, in the case that the touch input is at two touch points as illustrated in <figref idrefs="DRAWINGS">FIG. 5</figref> during period (a), the equivalence circuit of the resistive films <b>11</b> and <b>12</b>, etc. is that illustrated in <figref idrefs="DRAWINGS">FIG. 7</figref>. Note that in <figref idrefs="DRAWINGS">FIG. 7</figref>, Rt<b>1</b> and Rt<b>2</b> denote contact resistance. The voltage which is divided by the two touch points at this time takes a value at approximately the midpoint between the voltage which is divided by only one of the touch points and the voltage which is divided only by the other touch point. Therefore, in this case, the distance from the electrode <b>13</b> to the approximate midpoint between the two touch points, that is, the position of the midpoint in the X direction, can be obtained based on the voltage measured by the voltmeter <b>30</b>.

Next, in the case that the touch input is at two touch points as illustrated in <figref idrefs="DRAWINGS">FIG. 5</figref> during period (b), the equivalence circuit of the resistive films <b>11</b> and <b>12</b>, etc. is that illustrated in <figref idrefs="DRAWINGS">FIG. 8</figref>. Accordingly, the DC current that flows between the electrode <b>13</b> and the electrode <b>14</b> is measured by the ammeter <b>40</b>. At this time, the resistance between the electrode <b>13</b> and the electrode <b>14</b> is a combined resistance of the resistance Rx of the resistive film <b>11</b> itself, the contact resistance Rt<b>1</b> and Rt<b>2</b> which are connected in parallel with respect to portion of the resistive film <b>11</b>, and a resistance Ry<b>0</b> of the resistive film <b>12</b> between the two touch points. The resistance Ry<b>0</b> between the touch points is proportionate to the distance between the two touch points in the X direction. Therefore, the distance between the two touch points in the X direction can be obtained, based on the current measured by the ammeter <b>40</b>.

Note that as disclosed in aforementioned Patent Document 3, the combined resistance when touch input is performed at two points takes a value which is clearly lower than the resistance when touch input is performed at a single point, or when touch input is not being performed. Therefore, it is possible to subject the signal output from the ammeter <b>40</b> to a threshold value process, to discriminate whether there is no touch input or a touch input is being performed by a single touch point, or touch input is being performed by two touch points.

Detection of the position of a single touch point, the position of an approximate midpoint between two touch points, and the distance between two touch points in the X direction during periods (a) and (b) has been described above. During periods (c) and (d), the position of a single touch point, the position of an approximate midpoint between two touch points, and the distance between two touch points in the X direction are detected with respect to the Y direction. The methods of detection are the same as those with respect to the X direction, and therefore, a detailed description will be omitted.

The signals output by the voltmeter <b>30</b> are converted to voltage signals within a predetermined range by the converting circuit <b>31</b> of <figref idrefs="DRAWINGS">FIG. 2</figref>. Then, the voltage signals are A/D converted by the A/D converter <b>32</b>, and are output as digital signals Dv that indicate the position of a single touch point or the approximate midpoint of two touch points in the X and Y directions. The signals output by the ammeter <b>40</b> are converted to voltage signals within a predetermined range by the converting circuit <b>41</b> of <figref idrefs="DRAWINGS">FIG. 2</figref>. Then, the voltage signals are A/D converted by the A/D converter <b>42</b>, and are output as digital signals Di that indicate distance between two touch points in the X and Y directions.

The digital signals Dc that indicate the position of the approximate midpoint between two touch points and the digital signals Di that indicate the distance between the two touch points are input to the discriminating section <b>22</b>. The discriminating section <b>22</b> discriminates the trajectories of the two touch points <b>51</b> and <b>52</b>, based on changes in the signals Dv and Di over time.

The digital signals Dv include periodically repeating components that indicate the position of the approximate midpoint between two touch points in the X direction and the Y direction. Therefore, the discriminating section <b>22</b> can detect from what position and in what direction the aforementioned midpoint, that is, the two touch points, is moving, based on the values and the direction of change of each component. If the speed that the two touch points move at is high, the amount of change of the components per unit time will become greater. Therefore, the movement speed of the touch points can also be detected based on the amounts of change per unit time.

The digital signals Di include periodically repeating components that indicate the distance between two touch points in the X direction and the distance between two touch points in the Y direction. Therefore, the discriminating section <b>22</b> can detect from what values the distance between two touch points in the X direction and the distance between two touch points in the Y are increasing or decreasing, as well as the amounts of the increase or decrease. At this time, if the speed that the distance between two touch points changes is high, the amount of change of the components per unit time will become greater. Therefore, the speed at which the distance between the touch points is changing can also be detected, based on the amounts of change per unit time.

As described above, the discriminating section <b>22</b> is capable of discriminating the trajectories of the two touch points <b>51</b> and <b>52</b> indicated by arrows in (<b>1</b>), (<b>2</b>), (<b>3</b>), and (<b>4</b>) of <figref idrefs="DRAWINGS">FIG. 9</figref>, that is, gestures which are performed on the resistive film <b>12</b> by two fingers. The discriminating section <b>22</b> outputs discrimination signals Dout that indicate gestures which are detected in this manner.

Note that reference numeral <b>53</b> in <figref idrefs="DRAWINGS">FIG. 9</figref> denotes a point indicated by the digital signals Dv to be the approximate midpoint between the two touch points <b>51</b> and <b>52</b>. In addition, the trajectories of the touch points <b>51</b> and <b>52</b> capable of being discriminated by the discriminating section <b>22</b> are not limited to those illustrated in <figref idrefs="DRAWINGS">FIG. 9</figref>.

The gestures illustrated in <figref idrefs="DRAWINGS">FIG. 9</figref> may be utilized as triggers for performing various types of processes. As an example, in the case that the base plate <b>10</b> is equipped with display elements for displaying electronic books on the surface thereof, the gesture illustrated in (<b>1</b>) of <figref idrefs="DRAWINGS">FIG. 9</figref> may be a trigger to scroll a display range downward, the gesture illustrated in (<b>2</b>) of <figref idrefs="DRAWINGS">FIG. 9</figref> may be a trigger to temporarily close a page, the gesture illustrated in (<b>3</b>) of <figref idrefs="DRAWINGS">FIG. 9</figref> may be a trigger to lock page scrolling, and the gesture illustrated in (<b>4</b>) of <figref idrefs="DRAWINGS">FIG. 9</figref> may be a trigger to initiate page scrolling.

Alternatively, in the case that the base plate <b>10</b> is equipped with display elements that constitute a display screen for an electronic game, the trajectories of the two touch points may be displayed by the display elements, to create scenes in which text or figures are drawn in sand with two fingers, for example.

Note that in the embodiment described above, the voltage detection by the voltmeter <b>30</b> and the current detection by the ammeter <b>40</b> were performed separately at different points in time. However, the voltage detection and the current detection may be performed simultaneously.